An activated carbon is prepared from
gingelly oil cake (GOC) by using sulphuric acid treatment and its Cr(VI)
removal capacity is compared with that of commercial activated carbon (CAC).
The effect of experimental parameters such as pH, initial concentration,
contact time and adsorbents dose for Cr(VI) removal are studied. Langmuir,
Freundlich and Temkin models are tested to describe the equilibrium isotherms.
The maximum adsorption capacity of the adsorbents calculated from Langmuir
isotherm is found to be 30.58 mg/g and 25.13 mg/g for sulphuric acid treated
gingelly oil cake carbon (STGOC) and CAC respectively. R2 values show that both Langmuir and Freundlich models
fit well to explain the adsorption phenomenon for STGOC and CAC. The kinetic
data fits best to pseudo second-order model. FTIR analysis is used to obtain
information on the nature of possible interaction between adsorbents and metal
ions. SEM images confirmed the adsorption of Cr(VI) onto these adsorbents
through morphological observations. Gibbs free energy values showed the
feasibility of process and spontaneous nature of the adsorption. The adsorbents
are also tested for the removal of Cr(VI) from chrome plating wastewater and
found to remove Cr(VI) effectively.